<html>
<head>
  <title>数学运算</title>
  <style>
    body{background-color:#eee; font-size:14px;}
    table{*border-collapse:collapse; border-spacing:0; width:100%; color:#2B2B2B;}
    .bordered {border:solid #DADADA 1px; background-color:#fff；text-align:center;}
    .bordered tr,td{border: solid #DADADA 1px;padding: 10px;}
    .bordered tr:nth-child(5){text-align: right;}
    .bordered tr:nth-child(6){text-align: right;}
    .bordered tr:nth-child(1){font-weight: bold;}
    span{color:red;}
  </style>
</head>
<body>
<?php
  header('content-type:text/html;charset=utf-8');
const DISCOUNT=0.8;
$fruit1='香蕉';
$fruit2='苹果';
$fruit3='橘子';
$fruit1_num=2;
$fruit2_num=1;
$fruit3_num=3;
$fruit1_price=7.99;
$fruit2_price=6.99;
$fruit3_price=3.99;

$fruit1_total=$fruit1_num*$fruit1_price;
$fruit2_total=$fruit2_num*$fruit2_price;
$fruit3_total=$fruit3_num*$fruit3_price;
$total=($fruit1_total+$fruit2_total+$fruit3_total)*DISCOUNT;
$str="<table>";
$str .="<tr><td>商品名称</td><td>购买数量（斤）</td><td>商品价格（元/斤）</td></tr>>";
$str .="<tr><td>$fruit1</td><td>$fruit1_num</td><td>$fruit1_price</td></tr>";
$str .="<tr><td>$fruit2</td><td>$fruit2_num</td><td>$fruit2_price</td></tr>";
$str .="<tr><td>$fruit3</td><td>$fruit3_num</td><td>$fruit3_price</td></tr>";
$str .="<tr><td colspan='3'>商品折扣：<span>". DISCOUNT."</span></td></tr>";
$str .="<tr><td colspan='3'>打折后购买商品总价：{$total}元</td></tr>";
$str .="</table>";
echo $str;
?>
</body>
</html>